What are the requirements for the inlet water of the RO security filter?
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It is generally said that the SDI value is required for the feed water in reverse osmosis
When feeding water into the RO system, scale inhibitors and disinfectants must be added; otherwise, the RO system will clog quickly.
Regarding SDI, it requires RO feed water. But SDI
Security filters are primarily designed to prevent large particles from entering the high-pressure pump and damaging its impeller; they should not bear the filtering load
The security filter has been in use for quite a long time. Another issue is that your pre-treated water contains a high amount of colloids or organic substances, which causes blockages. We have encountered this situation before due to groundwater pollution.
We will find pharmaceutical manufacturers for you to work with in order to analyze the reasons behind the clogging of your reverse osmosis membranes. The possibility of contamination by suspended particles is low; it’s likely that the issue is caused by colloidal contamination, bacteria, or scaling due to an insufficient amount of scale inhibitor. Then, appropriate countermeasures are taken based on the actual situation.
Have you analyzed what causes blockages in reverse osmosis? Generally, membrane manufacturers require SDI
SDI requires RO feed water; it refers to the area before the safety filter. The filtration precision of this safety filter is 5um, and its function is merely to capture mechanical particles without damaging the surface of the RO membrane. The RO membrane structure also varies by section; scaling in the first section is mainly caused by microorganisms, while scaling in the second section is primarily due to calcium and magnesium deposits. For a certain type of structure, a bactericide can be added at the beginning of the processing stage, and a reducing agent can be added to the RO water inlet pipe for neutralization ； The two-stage structure may be due to: 1. no scale inhibitor being used, 2. too much scale inhibitor being used, or 3. the concentration ratio being set too high; appropriate adjustments can be made to rectify this.
I don’t know much about RO systems; it’s just a filter. I think it might be the large amount of impurities that cause the filter to get clogged so frequently. Could we consider adding another filter before the 5-micron filter to provide a second stage of filtration and capture most of the impurities?
I came in to read the replies from several experts like ls; basically, everything was already mentioned. It just still ignores the issue of the precision of the security filter elements. The precision claimed for these products is 5um, but in reality few manufacturers manage to meet this requirement.
Upstairs, the concept is wrong; it’s possible to achieve 5 microns – it’s just a matter of filtration efficiency. Perhaps imported filters have an efficiency of 80% while domestic ones have only 60%. 5 microns is achievable, haha